Audi A2 2001 - Page 181

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Possible deviation from spec‐
ification
Possible cause of fault Corrective action
• High pressure normal
• Low pressure too low (see
graph)
• The required cooling per‐
formance is obtained
♦ Actuation of A/C compressor reg‐
ulator valve -N280- malfunction‐
ing
♦ A/C compressor faulty.
– Check the A/C compressor regula‐
tor valve activation.
– Clean refrigerant circuit (flush with
refrigerant R134a, refer to
⇒ “1.4.13 Refrigerant Circuit Flush‐
ing With Refrigerant R134a“,
page 32 or blow through with com‐
pressed air and nitrogen, refer to
⇒ “1.4.12 Refrigerant Circuit Flush‐
ing With Compressed Air and Nitro‐
gen “, page 29 )
– Replace A/C compressor.
Note
Note the following if the malfunction is “high pressure normal, low
pressure too low“: the evaporator could be iced over even though
there is enough refrigerant in the circuit. Check the measured
values from the Evaporator vent temperature sensor -G263- and
the A/C compressor regulator valve -N280- actuation. If the meas‐
ured value from the evaporator vent temperature sensor is incor‐
rect, the evaporator may ice up or cooling output is not attained.
Check using Vehicle Diagnosis, Testing & Information System -
VAS5051B- (“OBD“ or “Guided Fault Finding for the A/C System“)
and ⇒ Heating, Ventilation and Air Conditioning; Rep. Gr. 87 or
⇒ A/C System; Rep. Gr. 87 (vehicle-specific repair manual).
Possible deviation from spec‐
ification
Possible cause of fault Corrective action
• High pressure normal or
too high
• Low pressure too high
(see graph)
• A/C compressor noise
(particularly after switch-
on)
• Required cooling output is
not attained
♦ Actuation of A/C compressor regulator
valve -N280- malfunctioning
♦ To much refrigerant in the circuit.
– Check the A/C compressor
regulator valve activation.
– Extract refrigerant from refrig‐
erant circuit
• If quantity of refrigerant ex‐
tracted roughly corresponds
to specified capacity:
– Replace A/C compressor.
• If quantity of refrigerant ex‐
tracted is substantially greater
than specified capacity:
– Charge the refrigerant circuit
– Repeat test
• High and low pressure
normal
• Required cooling output is
not attained
♦ Actuation of A/C compressor regulator
valve -N280- malfunctioning
♦ To much refrigerant oil in the circuit.
– Check the A/C compressor
regulator valve activation.
– Discharge refrigerant circuit
Audi 100 1991 ➤ , Audi 80 1992 ➤ , Audi A1 2011 ➤ , Audi A2 2001 ➤ , A ...
Refrigerant R134a Servicing - Edition 01.2011
4. Diagnosis and Testing 177